From 8cf2461787d8870b637f04c3c1cc9e7b2c3ade7d Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sun, 19 Jan 2014 08:26:37 +0000 Subject: [PATCH] percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask commit 6f6b5d1ec56acdeab0503d2b823f6f88a0af493e upstream. This patch changes percpu_ida_alloc() + callers to accept task state bitmask for prepare_to_wait() for code like target/iscsi that needs it for interruptible sleep, that is provided in a subsequent patch. It now expects TASK_UNINTERRUPTIBLE when the caller is able to sleep waiting for a new tag, or TASK_RUNNING when the caller cannot sleep, and is forced to return a negative value when no tags are available. v2 changes: - Include blk-mq + tcm_fc + vhost/scsi + target/iscsi changes - Drop signal_pending_state() call v3 changes: - Only call prepare_to_wait() + finish_wait() when != TASK_RUNNING (PeterZ) Reported-by: Linus Torvalds Cc: Linus Torvalds Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Jens Axboe Signed-off-by: Kent Overstreet Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/iscsi/iscsi_target_util.c | 8 ++++++-- drivers/vhost/scsi.c | 2 +- include/linux/percpu_ida.h | 3 ++- lib/percpu_ida.c | 16 +++++++++------- 4 files changed, 18 insertions(+), 11 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index b0cac0c..f633a87 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -156,9 +156,13 @@ struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, gfp_t gfp_mask) { struct iscsi_cmd *cmd; struct se_session *se_sess = conn->sess->se_sess; - int size, tag; + int size, tag, state = (gfp_mask & __GFP_WAIT) ? TASK_UNINTERRUPTIBLE : + TASK_RUNNING; + + tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state); + if (tag < 0) + return NULL; - tag = percpu_ida_alloc(&se_sess->sess_tag_pool, gfp_mask); size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size; cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size)); memset(cmd, 0, size); diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index e663921..d300fd9 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -728,7 +728,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, } se_sess = tv_nexus->tvn_se_sess; - tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC); + tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING); if (tag < 0) { pr_err("Unable to obtain tag for tcm_vhost_cmd\n"); return ERR_PTR(-ENOMEM); diff --git a/include/linux/percpu_ida.h b/include/linux/percpu_ida.h index 0b23edb..67de9b7 100644 --- a/include/linux/percpu_ida.h +++ b/include/linux/percpu_ida.h @@ -4,6 +4,7 @@ #include #include #include +#include #include #include #include @@ -51,7 +52,7 @@ struct percpu_ida { } ____cacheline_aligned_in_smp; }; -int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp); +int percpu_ida_alloc(struct percpu_ida *pool, int state); void percpu_ida_free(struct percpu_ida *pool, unsigned tag); void percpu_ida_destroy(struct percpu_ida *pool); diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c index bab1ba2..6f6a92d 100644 --- a/lib/percpu_ida.c +++ b/lib/percpu_ida.c @@ -142,22 +142,22 @@ static inline unsigned alloc_local_tag(struct percpu_ida *pool, /** * percpu_ida_alloc - allocate a tag * @pool: pool to allocate from - * @gfp: gfp flags + * @state: task state for prepare_to_wait * * Returns a tag - an integer in the range [0..nr_tags) (passed to * tag_pool_init()), or otherwise -ENOSPC on allocation failure. * * Safe to be called from interrupt context (assuming it isn't passed - * __GFP_WAIT, of course). + * TASK_UNINTERRUPTIBLE, of course). * * @gfp indicates whether or not to wait until a free id is available (it's not * used for internal memory allocations); thus if passed __GFP_WAIT we may sleep * however long it takes until another thread frees an id (same semantics as a * mempool). * - * Will not fail if passed __GFP_WAIT. + * Will not fail if passed TASK_UNINTERRUPTIBLE. */ -int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) +int percpu_ida_alloc(struct percpu_ida *pool, int state) { DEFINE_WAIT(wait); struct percpu_ida_cpu *tags; @@ -184,7 +184,8 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) * * global lock held and irqs disabled, don't need percpu lock */ - prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE); + if (state != TASK_RUNNING) + prepare_to_wait(&pool->wait, &wait, state); if (!tags->nr_free) alloc_global_tags(pool, tags); @@ -201,7 +202,7 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) spin_unlock(&pool->lock); local_irq_restore(flags); - if (tag >= 0 || !(gfp & __GFP_WAIT)) + if (tag >= 0 || state == TASK_RUNNING) break; schedule(); @@ -209,8 +210,9 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) local_irq_save(flags); tags = this_cpu_ptr(pool->tag_cpu); } + if (state != TASK_RUNNING) + finish_wait(&pool->wait, &wait); - finish_wait(&pool->wait, &wait); return tag; } EXPORT_SYMBOL_GPL(percpu_ida_alloc); -- 2.7.4